Method and apparatus for scrub preview services

ABSTRACT

In accordance with an embodiment of the present invention, a method of streaming a media preview includes delivering a preview data having preview information from a media file to be streamed. The preview data has a multi-dimensional hierarchical data structure has a plurality of layers with increasing content of the preview information in each layer of the plurality of layers. The preview data is configured to provide an adaptive and scalable preview service.

This application claims the benefit of U.S. Provisional Application No.61/384,166, filed on Sep. 17, 2010, entitled “Method and Apparatus forDifferentiated Scrub Preview Services,” and U.S. Provisional ApplicationNo. 61/428,776, filed on Dec. 30, 2010, entitled “Method and Apparatusfor Processing Scrub Description,” which applications are herebyincorporated herein by reference.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application relates to the following co-pending and commonlyassigned patent application Ser. No. 13/233,882, filed Sep. 15, 2011,which application is hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to media processing, and moreparticularly to a system and method for scrub preview services.

BACKGROUND

In recent years, media consumption has dramatically increased. This hasresulted in a rapid increase in available media content. Consequently,consumers of the media have to select from a large array of availablemedia content. However, there is no easy mechanism for making thisselection.

Consumers of textual data have a much better experience than mediaconsumers due to the availability of summaries, snippets, keywords, etc.For example, short summaries of large textual content provide users withan abstract of the content. This allows the user to rapidly select thearticles/web pages to read.

In contrast, media consumers have to sort through the actual footage ofthe media before selecting a suitable media (or a portion of the media)to watch. For example, in a typical media player, a consumer must usethe forward button to play the media stream at a faster frame rate,which mutes the audio channel. Further, the user may want to watch onlya certain portion of the media stream, e.g., the financial summary in anews feed so that he can judge whether the financial news is worthwatching. However, the user is likely to be frustrated because of thedifficulty in identifying the appropriate relevant portion of the mediastream and the necessity to watch the media stream to get the neededsummary. Such ineffective means introduce inefficiencies in mediaselection and result in a degraded user experience.

SUMMARY OF THE INVENTION

These and other problems are generally solved or circumvented, andtechnical advantages are generally achieved, by illustrative embodimentsof the present invention.

In accordance with an embodiment of the present invention, a method ofgenerating a media preview of a media stream comprises generating apreview data by extracting preview information from a media file to bestreamed. The preview data comprises a multi-dimensional hierarchicaldata structure having a plurality of layers with increasing content ofthe preview information in each layer of the plurality of layers. Thepreview data is configured to provide an adaptive and scalable previewservice.

In accordance with another embodiment of the present invention, a methodof streaming media comprising a media preview comprises delivering apreview data comprising preview information from a media file to bestreamed. The preview data comprises a multi-dimensional hierarchicaldata structure having a plurality of layers with increasing content ofthe preview information in each layer of the plurality of layers. Thepreview data is configured to provide an adaptive and scalable previewservice.

In accordance with another embodiment of the present invention, a methodof receiving a media preview of a media stream comprises sending apreview data request to a preview server. The preview data requestcomprises a request for preview data. The method further comprisesreceiving a preview data comprising preview information from a mediafile to be streamed. The preview data comprises a multi-dimensionalhierarchical data structure having a plurality of layers with increasingcontent of the preview information in each layer of the plurality oflayers.

In accordance with another embodiment of the present invention, anapparatus for generating a media preview of a media stream comprises apreview data generator. The preview data generator under variousembodiments is configured to generate a preview data by extractingpreview information from a media file to be streamed. The preview datacomprises a multi-dimensional hierarchical data structure having aplurality of layers with increasing content of the preview informationin each layer of the plurality of layers. The preview data generator isconfigured to provide preview data for an adaptive and scalable previewservice.

In accordance with another embodiment of the present invention, anapparatus for streaming a media preview of a media comprises a previewdata sender configured to deliver a preview data. The preview datacomprises preview information for a media file being streamed. Thepreview data comprises a multi-dimensional hierarchical data structurehaving a plurality of layers with increasing content of the previewinformation in each layer of the plurality of layers. The preview datasender is configured to provide an adaptive and scalable previewservice.

In accordance with another embodiment of the present invention, anapparatus for receiving media having a media preview comprises a previewdata sender configured to send a preview data request to a previewserver. The preview data request comprises a request for a preview datafor a media file being received. The preview data receiver is configuredto receive the preview data comprising preview information for the mediafile. The preview data comprises a multi-dimensional hierarchical datastructure having a plurality of layers with increasing content of thepreview information in each layer of the plurality of layers.

Advantageously, embodiments of the invention allow full video previewand ultra-fast preview start up capability even under narrow bandwidthconditions.

The foregoing has outlined rather broadly the features of an embodimentof the present invention in order that the detailed description of theinvention that follows may be better understood. Additional features andadvantages of embodiments of the invention will be describedhereinafter, which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiments disclosed may be readily utilized as a basisfor modifying or designing other structures or processes for carryingout the same purposes of the present invention. It should also berealized by those skilled in the art that such equivalent constructionsdo not depart from the spirit and scope of the invention as set forth inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawing, in which:

FIG. 1 describes a preview system for generating, delivering, andrendering the preview system in various embodiments of the invention;

FIG. 2 schematically indicates the typical media player components andtheir relative positions in a media player;

FIG. 3 illustrates a schematic of a media player illustrating a previewusing an overlay preview window;

FIG. 4 illustrates a schematic of a media player illustrating a previewusing a convoy preview window;

FIG. 5 illustrates a schematic of a media player illustrating a previewusing tile preview windows;

FIG. 6 illustrates a schematic of a media player illustrating a previewwith list preview;

FIG. 7 illustrates a schematic of a media player illustrating a previewusing thumbnails preview;

FIG. 8 illustrates operations in accordance with an embodiment of theinvention for preview generation;

FIG. 9 illustrates operations in accordance with an embodiment of theinvention for preview delivery;

FIG. 10 illustrates operations in accordance with an embodiment of theinvention for preview rendering;

FIG. 11 illustrates a scrub description preview system in accordancewith embodiments of the invention;

FIG. 12 illustrates operations of generating description based scrubpreview in a stand-alone preview system;

FIG. 13, which includes FIGS. 13A and 13B, illustrates one sampleembodiment using aligned scrub description scheme, wherein FIG. 13Aillustrates a scrub description data structure and FIG. 13B shows anexample;

FIG. 14 illustrates one sample embodiment illustrating more than onedegree of freedom of scrub description;

FIG. 15 illustrates a scheduling algorithm for a standalone previewsystem for the operations of the preview description delivery inaccordance with an embodiment of the invention;

FIG. 16 illustrates a scheduling algorithm for a standalone previewsystem for the operations of the preview description delivery inaccordance with an embodiment of the invention, wherein the schedulingalgorithm delivers granular layers from within the layers of the scrubdescription data;

FIG. 17 illustrates a sample embodiment of a preview descriptionrendering process at a media player receiving preview data in accordancewith an embodiment;

FIG. 18 illustrates a sample embodiment of a preview descriptionrendering process at a media player receiving preview data in accordancewith an embodiment, wherein the media player receiver granular layersfrom within the layers of the scrub description data;

FIG. 19 illustrates a media player receiving preview data havingmultiple degrees of freedom in accordance with an embodiment of theinvention;

FIG. 20 illustrates a sample interface for a dual-view scrub preview inaccordance with an embodiment of the invention;

FIG. 21 illustrates a media player rendering a media rich scrub previewwindow in accordance with an embodiment of the invention;

FIG. 22 illustrates a preview generation unit in accordance withembodiments of the invention;

FIG. 23 illustrates a preview delivery unit in accordance withembodiments of the invention;

FIG. 24 illustrates a preview receiver unit in accordance withembodiments of the invention;

FIG. 25 illustrates a representative a preview server in accordance withembodiments of the invention;

FIG. 26 illustrates a representative a media player in accordance withembodiments of the invention; and

FIG. 27 illustrates a generic architecture of a system implementing thedifferentiated scrub preview in accordance with embodiments of theinvention.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the embodiments andare not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of various embodiments are discussed in detailbelow. It should be appreciated, however, that the present inventionprovides many applicable inventive concepts that can be embodied in awide variety of specific contexts. The specific embodiments discussedare merely illustrative of specific ways to make and use the invention,and do not limit the scope of the invention.

In the typical online media platforms or delivery systems today,on-demand media content (especially video) is presented via powerfulmedia players which allow the users to randomly seek to any spot tocontinue the video playback. The media content is consumed eitherlinearly (by default, for example, by clicking a web thumbnail whichleads to a media playing in a media player) or randomly by the end userby dragging the play-head of the media player forward or backward to arandom spot. These types of media consumption models do not provide theend users effective consumption of media content. The random drag(scrub) of play-head may appear to provide infinite flexibility to theend users, but in fact the dragging to a spot involves random guess workand users often have to watch the content for a little bit to decide ifthis is worth continuing or another random drag is in order.

Preview is a natural tool for people to sample the content of a videobefore watching it. Online video streaming traffic accounts for thelion's share of the internet traffic today and continues to grow.Customers are demanding for more content, more flexibility, more servicecapability, more personalization, and better qualities. Providing largeamount of preview data can take up considerable network deliveryresources. To control the consumption of delivery resources, e.g., thedelivery network bandwidth consumption, the preview delivery service arelimited to the network condition, resource availability, as well asservice capabilities. However, such brute force restriction of previewcontent degrades experience for all customers.

As described further below, an adaptive scrub preview scheme canovercome these limitations. The problem of lacking reference informationduring the active consumption of online media (i.e., drag of play-headin a player to seek for a more desirable spot to continue) may beovercome with a scrub preview scheme. End users are provided a series ofpreview data such as preview images (or even lower resolution videoclips) as the end users drag the play-head along the progress bar. Thus,the system greatly enhances active media consumption of the end users byallowing them to seek a preferred spot to continue the mediaconsumption, and hence greatly improves the end user media consumptionexperience.

Embodiments of the invention describe an adaptive service to offercustomers fair and superior service capability with the service providerbeing able to gain increased average revenue per user (ARPU).Embodiments of the present invention discloses a fair and differentiatedpreview service scheme including a differentiated scrub preview servicescheme based on a multi-layer data structure, multi-stage deliveryscheme, and offers multi-style presentation format. The proposed schemeas described in various embodiments can further improve userexperiences, service personalization capability, as well as otherpreview service capabilities.

The adaptive scrub preview scheme as described in various embodiments isscalable, flexible and extensible. Some embodiments of the presentinvention provide an ultra-fast preview startup and switchingfunctionality. Consequently, the scrub preview is capable of supportingpreview functions in mobile network or other networks with limitedbandwidth or networks with frequent bandwidth fluctuations. Someembodiments of the present invention provide dual view and toggle viewscrub previews which offer richer service capability. Embodiments of theinvention also offer additional preview styles for better personalizedpreview services.

A number of new features and advantages are provided by embodiments ofthe present invention. For example, one aspect relates to a system tosupport adaptive and scalable preview services with preview generation,preview delivery, and preview rending. Another aspect relates to anadaptive preview service scheme based on a multi-layer data structure,multi-stage delivery scheme, and provides multi-style presentationformat. Yet another aspect relates to a differentiated scrub previewservice scheme with flexible and personalization enabled servicecapability. Yet a further aspect relates to an adaptive and scalablepreview service system that supports single or multiple service providerbased preview for IP video delivery services.

Embodiments of the present invention provide advantages and distinctionsover alternative technologies. In traditional preview system, thepreview functions are usually simple, easy to use, but non-scalable,without personalization capability, with limited ability to adapt to thechanging network and other environment conditions, and with littlepresentation flexibility and adaptation capability. In variousembodiments, the present invention offers a wide range of scalable andadaptive preview service capabilities. The scalability and flexibilitymake it possible for an IP video delivery service provider to supportdifferentiated preview services for added ARPU. A differentiated previewservice scheme with a multi-layer data structure, multi-stage deliveryscheme, and multi-style presentation format is also disclosed.

Scrub preview provides an incorporated service that is part of the IPvideo delivery service. Embodiments of the present invention offer meansto support an independent differentiated preview service via a previewservice system that offers both single and multiple service providerbased preview service capability for IP video delivery services.Versions of scrub video are flexible, scalable and extensible previewscheme but might not support differentiated service scheme. Embodimentsof the invention support a wide range of differentiated previewservices.

A generic embodiment of the preview system for generating, delivering,and rendering the preview system will be described using FIG. 1, 22-24.A first set of embodiments of the present invention will be describedfor providing a scrub preview service based on preview data type usingFIGS. 8-10. A second set of embodiments of the present invention will bedescribed for providing a scrub description based preview service usingFIGS. 11-21.

FIG. 1 describes a preview system for generating, delivering, andrendering the preview system in various embodiments of the invention.

Referring to FIG. 1, a typical preview system in accordance withembodiments of the invention includes three main components, namelyPreview Generation (PG 10), Preview Delivery (PD 20), and PreviewRendering (PR 30). PG 10 takes a media stream and generates previewdata. PD 20 delivers the preview data to the client (media player). Themedia player receiving the preview data renders the preview to thedisplay (PR 30).

In various embodiments, the preview may be rendered using different typeof client interface configurations. FIG. 2 to FIG. 7 illustrate sixsample preview client interface configurations. Notice that these aremerely examples. The present invention does not limit the type ofpreview interface configurations. One skilled in the art can easilyimplement the current invention in different interface configurations.

FIG. 2 schematically indicates the typical media player components andtheir relative positions in a media player. FIG. 2 illustrates aschematic of a media player 50 illustrating a preview using a scrubpreview window 60 and a range indicator 70 indicating the validity ofthe preview.

FIG. 2 shows a reduced size scrub preview window 60 which can also beused for the description based scrub preview as will be describedfurther below (FIGS. 11-21). The size of the scrub preview window 60 mayvary from small to full player window size depending on applicationneeds. When a media player user initiates a scrub preview, the userdrags the play-head forward or backward along the preview bar.

The preview bar may be the playback progress bar, or it may be aseparate bar. The granularity of the preview is, in general, proportionto the length of the video. To offer personalized experience, however, ascalable preview rendering function may be realized using one or moreembodiments of the present invention. Furthermore, a localized scalablepreview rendering capability can be achieved where the scalability ofthe preview is proportional to the play-head dragging speed withlocality sensitivity. Users can easily browse through a video from thebeginning to the end or back and forth. A user can also start theplayback instantly at any preview position and start to watch the videothereafter. The preview description data stream delivery schemeoptimizes the video preview start up time and ensures the previewplayback has no glitch.

FIG. 3 illustrates a schematic of a media player 50 illustrating apreview using an overlay preview window 80. FIG. 4 illustrates aschematic of a media player 50 illustrating a preview using a convoypreview window 90. FIG. 5 illustrates a schematic of a media player 50illustrating a preview using tile preview windows 110. FIG. 6illustrates a schematic of a media player 50 illustrating a preview withlist preview 120. FIG. 7 illustrates a schematic of a media player 50illustrating a preview using thumbnails preview 130.

In various embodiments, the preview delivery service may be adaptedbased on some discrimination functions or service configurations tocontrol the delivery resources consumption, e.g., the delivery networkbandwidth consumption. In various embodiments, a service provider, mayprovide several classes of services, SC(1), SC(2), . . . SC(X).Different classes of services may be set apart by the servicecapability, the subscription fees, and other suitable parameters as maybe identified by one skilled in the art. Customers subscribing to ahigher class subscription, e.g., SC(X), may get better Quality ofService (QoS) and/or Quality of Experience (QoE) guarantees whereascustomers subscribing to a lower class subscription, e.g., SC(1), mayget significantly less service capability support compared with that ofthe higher class subscription customer.

For instance, a SC(X) subscriber may get the best type of previewconfiguration, the highest amount of description data, the mostflexibility to preview a video, and the highest quality with the highestresolution of the preview video. In contrast, a SC(1) subscriber mayexperience some service capability loss and may only get the minimumamount of data delivered to its player with a minimum support on thepreview configurations and a minimum flexibility on how the video can bepreviewed. Hence, while the SC(X) subscriber may enjoy a full range ofpreview service capabilities and personalize the service based on itsown preference, the SC(1) subscriber may only enjoy a limited previewservice capability with limited personalization.

Because of such differentiation between different customers, a serviceprovider can balance the resource distribution when the network resourceor other related types of resources are limited. Accordingly, this typeof differentiated preview service can provide fair services to itssubscriber i.e. higher paying customers receive better service thanlower paying customers.

Further details on implementing an embodiment of the invention isdescribed using FIGS. 8 and 9.

FIG. 8 illustrates operations in accordance with an embodiment of theinvention for preview generation.

Different types of preview data D(i), i=[1,I], are first defined (step210). For instance, let a first type of preview data D(1) may be apreview video data, a second type of preview data D(2) may be a previewaudio data, a third type of preview data D(3) may be keyframe images, afourth type of preview data D(4) may be preview content descriptiontext, a fifth type of preview data D(5) may be preview contentdescription image, a sixth type of preview data D(6) may be a preview ofrelevant images, a seventh type of preview data D(7) may be a previewrelevant text, etc.

The preview data may comprise a hierarchical structure. In other words,multiple layers of preview data may be used, each layer having moreinformation than an underlying layer. For example, a higher layer mayprovide a higher resolution preview, a longer length preview, and/orvideo parameters e.g. color versus grayscale, bitrate etc. In ahierarchical preview data having J layers, the j^(th) layer of the typeD(i) data can be denoted as P(j)|D(i), j=[1,J]. For instance, if D(1)represents preview video data, P(1)|D(1) could be the first layer of thepreview video data with a resolution 120×90 in gray scale, P(2)|D(2)could be the second layer of the preview video data with a resolution240×180 in gray scale, and so on.

Next, the service class is defined (step 220). Let service class SC(x),x=[1,X], be the preview service types offered by a service provider withservice class SC(X) being the highest level of service class or VIPservice class. The VIP service class provides consumers the ultimateservice capability and flexibility and let service class SC(1) be thelowest level of service class, e.g., cheapest service which offers aminimum preview service capability.

In addition, user specified parameters may also be defined (step 230).For example, β(k)|D(i) defines the user specified parameter for previewdata type D(i) to be delivered to the client. For instance, β(1)|D(1)may represent a low resolution gray scale video, β(2)|D(1) may representa low resolution color video, β(3)|D(1) may represent a mediumresolution video, β(4)|D(1) may represent a high resolution video,β(1)|D(4) may represent a minimum text description, β(2)|D(4) mayrepresent a moderate text description, and β(3)|D(4) may represent amaximum text description, etc.

For each type of service, a maximum allowed service class profile isdefined (step 240). For example, a service class profileSCP_(max)(x)=[P(j¹*)|D(1), P(j²*)|D(2), . . . , P(j^(I)*)|D(I)] whereP(j^(i)*)|D(i) denotes the maximum layers of data for D(i) type ofpreview data. Thus, maximum allowed service class profile SCP_(max)(x)is the highest possible preview that is available.

As illustrated in step 250, an instance service class profile for eachuser L is defined as SCP_(ins)(x)=[P(j¹′)|D(1), P(j²′)|D(2), . . . ,P(j^(I)′)|D(I)] where P(j^(I)′)|D(i) denotes the specified layers ofdata for D(i) type of preview data with j^(i)′≦j^(i)*. That is, theservice provider may specify a set of rules for the preview datadelivery that corresponds to each parameter to identify the layerassociated for each preview data type D(i). In various embodiments, adefault setting maybe used based on user preferences and profiles aswell as the service class level she subscribes to.

In one or more embodiments, the client may also interactively adjust thepreview service using some simple click based interfaces at the clientside if her subscription level includes such service support. That is,the default instance service class profile SCP_(ins)(x)|L default may ormay not equals to instant service class profile SCP_(ins)(x)|L instant.But, in various embodiments, SCP_(ins)(x)|L default or SCP_(ins)(x)|Linstant cannot exceed beyond the maximum allowed service class profileSCP_(max)(x). The selected type (parameter) of preview servicecapability shall be translated into an adjustment or adaptation of a newor different set of preview data being delivered to the client by theserver.

An embodiment of the invention for preview delivery will be describedusing FIG. 9.

A server receives a preview service request from a client (step 260).Once a server receives a preview service request indicating a default orinstant service class profile with Q(x)|Ldefault or Q(x)|Linstant. Theserver translates the request into the corresponding service classprofile, e.g., SCP_(ins)(x)|L default or SCP_(ins)(x)|L instant (step270). Next, the server parses the requested profile by extracting theappropriate layer of the preview data, e.g., P(j¹′)|D(1)=120×90 colorvideo (step 280). The extracted preview data is packaged and scheduledinto a preview data stream. The preview data stream is delivered to theclient side from which the preview request arose (step 290). All thesesteps may be performed in a single edge server or alternatively over acombination of network nodes, depending on the content delivery systemcapability and configurations. Once the client receives the preview datapackage, it decodes the package. The preview data may be rendered basedon a default player setting or a user specification, and enables theuser to enjoy the preview content instantly. Synchronization to theoriginal media stream may be needed so that the preview data representsa particular location on the original media stream.

A differentiated preview service can be implemented for any kind ofpreview service. In the following, a sample embodiment fordifferentiated scrub preview service scheme is discussed. Several typesof scrub previews including keyframe based scrub preview, descriptionbased scrub preview, and dual view scrub preview may be used in variousembodiments of the invention. With differentiated scrub preview service,a highest class subscriber SC(X) may get the dual-view scrub previewsupport with both the scrub description data and the keyframe datadelivered to its player. However, a lowest class subscriber SC(1) mayexperience some service capability loss and may only get one or twolower layers of the scrub description data delivered to its player.Hence, while the highest class subscriber SC(X) may enjoy a full scrubpreview service and personalize the service based on its own preference,the lowest class subscriber SC(1) may only enjoy a coarse level scrubpreview presented in a single text based style. When the networkresource or other related types of resources are limited or constraint,this type of differentiated scrub preview service can help a serviceprovider to balance the resource distribution and provide fair servicesto its subscriber.

In yet another embodiment of the present invention, an independentpreview service can be offered. Any user can subscribe to the previewservice with or without the subscription to the VoD or real time videodelivery service. A user subscribed to the preview service can beconnected directly to the preview server at her request. The servershall deliver the preview content to the user based on her subscriberservice class, the user profile, the network and device condition, etc.In this embodiment, the preview service server maybe connected tomultiple video delivery servers that are part of a single or multiple IPvideo delivery service providers.

FIG. 10 illustrates operations in accordance with an embodiment of theinvention for preview rendering.

Referring to FIG. 10, a client, e.g., media player send a request forpreview data (Step 1010). The media player may also send further userinformation such as a user specified information β (described above) forpreview data requested (Step 1020). For instance, the media player mayrequest that the first layer data may be transmitted as a low resolutiongray scale video. The media player receives the corresponding previewdata (Step 1030). Next, the media player renders the preview data to adisplay (Step 1040).

Another embodiment of the present invention using description basedpreview will next be described using FIGS. 11-21.

Embodiments of the present invention extend the scrub preview scheme toprovide ultra-fast preview startup functionality. Instead of keyframebased scrub preview, in this embodiment of the present invention,description based scrub previews are used. The preview can startinstantly without affecting the playback of the video, even in very lowbandwidth network conditions. In a separate embodiment, the presentinvention describes the systems and scheme to achieve an additionalscrub preview style called dual view scrub preview that takes advantageof both the description based and the keyframe based scrub preview. Thedual view scrub preview offers additional personalized servicecapability. Embodiments of the present invention address the system andmethod to realize the description based scrub preview as well as thedual view scrub previews in a networked media distribution system withan online media player.

FIG. 11 illustrates a scrub description preview system in accordancewith embodiments of the invention.

Referring to FIG. 11, the preview description system in accordance withembodiments of the invention includes three main components, namelyPreview Description Generation (PDG 310), Preview Description Delivery(PDD 320), and Preview Description Rendering (PDR 330). This is similarto the scrub preview system discussed in above using FIG. 1.

PDG 310 is a process to extract and prepare necessary previewdescription, i.e., the scrub description data, for effective deliveryand rendering. PDG 310 may happen either during an Ingest Process orafter the Ingest Process. If the Content Delivery Process is amulti-step process, the PDG 310 may happen in any step. In variousembodiments, the PDG 310 may generate additional content descriptionmetadata beyond the existing metadata in order to support the Fast MediaPreview feature.

PDD 320 is a process whereby necessary Preview Description data andother metadata are delivered to the end user media player for previewrendering. The detailed algorithm of when and how to deliver whichpreview description data file(s) will be described further below usingFIGS. 15 and 16.

PDR 330 is a process by which delivered preview description data, i.e.,the scrub description data files are rendered to the end user asplay-head is being dragged to seek a desired position. The PDR 330process is sufficiently general so that it can be implemented easily byany player with a simple PlugIn module in various embodiments.

The description based scrub preview may be implemented in a stand-alonepreview system. Alternatively, it may be an add-on layer to the originalkeyframe based scrub preview system. In addition, in one or moreembodiments, it can be employed in combination with the keyframe basedscrub preview to achieve dual-view scrub preview or toggled scrubpreview. For ease of presentation, we shall use scrub description in thefollowing discussion. A scrub description is a set of text that can beused to describe the content of the media or the information associatedwith the content of the media at a particular time frame, maybedisplayed in a static or dynamic manner, and can facilitate mediapreview.

Embodiments of the PDG, PDD, and PDR implemented a description basedscrub preview in a stand-alone preview system will be described.

FIG. 12 illustrates operations of generating description based scrubpreview in a stand-alone preview system (PDG 310 of FIG. 11).

PDG 310 includes scrub description data extraction, scrub descriptionmanagement data generation, i.e., manifest file and index file creation,and scrub description data stream creation components. In accordancewith embodiments of the invention, the preview data should satisfyseveral requirements to facilitate a fast scrub preview function.

First, the scrub description data should be small in size. To providefull video preview and ultra-fast preview start up capability especiallyin narrow bandwidth conditions, the preview media data stream, i.e., thescrub description data, is very small in size. Consequently, delivery ofthe preview media data stream will not hinder the delivery of theoriginal media data stream or affect the playback experience of theoriginal media data stream. To achieve that, the scrub description datais designed to be compact.

Second, for a quality preview experience, the preview content shouldcapture the essence of the original media data stream. That is the scrubdescription should tender accurate content information about theparticular segment of the video content in preview.

Third, to offer fast playback switching from any preview point to thecorresponding original media stream point and vice versa, it is desiredthat the scrub description data streaming is well synchronized with theoriginal media stream.

FIG. 13, which includes FIGS. 13A and 13B, illustrates one sampleembodiment using aligned scrub description scheme, wherein FIG. 13Aillustrates a scrub description data structure and FIG. 13B shows anexample.

Embodiments of the invention use a scalable description scheme tofacilitate scalable full video preview and fast preview start up. Thelength of the video is denoted a total time length Γ. The total timelength Γ is determined for a given video stream (step 1210). Assume thelevel of scalability is K, i.e., there are K layers of descriptionavailable for preview, from the coarsest layer 1 to the finest layer K(step 1220).

Referring to FIG. 13A, a plurality of layers (1, 2, . . . , K) for thepreview data D is illustrated. In each layer, the media stream length isdivided into a number of time segments. The duration of the timesegments decreases with increasing layer thereby increasing the amountof preview data.

The scrub description for each layer is defined over each time segment(step 1240). As schematically illustrated in FIG. 13A, the i^(th) scrubdescription of the k^(th) layer denoted as D(i, k) is defined. Thei^(th) scrub description of the k^(th) layer D(i, k) represents thepreview description covering a i^(th) time segment of the k^(th) layerΓ(i, k). The total number of scrub descriptions (I_(k)) in a layer k isdefined. That is,

${{\sum\limits_{i = 1}^{I_{k}}{\Gamma( {i,k} )}} = \Gamma},$k=[1, K]. For example, as illustrated in FIG. 13A, the first scrubdescription of the first layer D(1, 1) has a longer time segment thanthe first scrub description of the second layer D(1, 2).

In various embodiments, the scrub description of layer k may be eitheraligned or not aligned with the scrub description of layer k−1. Here, iffor i=[1,I_(k)],

${{\Gamma( {i,k} )} = {\sum\limits_{i^{*} = j}^{J_{i}}{\Gamma( {i^{*},{k - 1}} )}}},$layer k−1 is deemed to be aligned to layer K. To facilitate localizedscalability, most embodiments of the invention use an aligned scheme.

FIG. 13B illustrates an example using the embodiments of the scrubdescription data structure described above. As illustrated in FIG. 13A,the first layer is divided into three time segments while the secondlayer is divided into seven time segments. Each time segment in eachlayer contains a scrub description. For example, the first scrubdescription in the first layer is “Toyota recalls.” As illustrated inFIG. 13B, a user may be able to preview the third scrub description ofthe first layer D(3,1) or the sixth scrub description of the secondlayer D(6,2).

To improve user experience, especially personalized preview experience,a second dimension scalability, description scalability is alsodesirable. That is, instead of a single scrub description D(i, k), Hdegrees of description D(h, i, k) may be implemented for the i^(th)scrub description of the k^(th) layer. The lowest degree (h=1) may usethe shortest description, i.e., the most abstract version of thedescription. The highest degree (h=H) may use the longest description,i.e., the most detailed version of the description.

FIG. 14 illustrates one sample embodiment showing more than one degreeof freedom of scrub description. In FIG. 14, two degrees of freedom isselected and therefore two preview windows are displayed by the mediaplayer 50. In various embodiments, the scrub preview degree may beselected based on the specific user preference profiles. Alternatively,in one embodiment, the lowest description (h=1) may be displayed bydefault until the end user specifies (or alternatively requests) adifferent degree for display. A user may also easily toggle the viewsfor different description details, i.e. different degree views, usinghot keys or control buttons.

Evidently, i^(th) time segment of the k^(th) layer Γ(i, k) helps tofoster the alignment between scrub description D(h, i, k) or D(i, k) andthe original media content. To enable fast playback, a multi-layer mediasegmentation scheme followed by the multilayer scrub descriptiongeneration process maybe employed in various embodiments.

To enable a quality preview experience, the scrub description D(i, k)should accurately describe the content stream within the time frameΓ(i,k). To achieve that, many scrub description D(i, k) extractionschemes may be used as known to one skilled in the art. For example, theextraction scheme may be selected based on preprocessing the mediastream.

In one sample embodiment, scrub description D(i, k) maybe generatedusing the content description metadata. Content description metadata maybe generated from many different sources including manual annotation,semi-automatic annotation, and automatic annotations which may includevideo content analysis, audio content analysis, text analysis, andspeech recognition. Some part of the content description metadata mayalso be collected using web crawling.

To achieve fast media preview even in narrow bandwidth conditions, thescrub description D(i.k) should, in general, be small in size whilecontent description metadata for different content may vary in size.Hence a scrub description extraction process is often necessary togenerate scrub description D(i,k) for a given video. Many differentextraction schemes can be used in various embodiments. In one or moreembodiments, semantic and context based analysis may be used forproviding the best extraction results. Alternatively, in someembodiments, key phrase based extraction may provide an easy toimplement and fast executable scheme. The present invention does notlimit the type of extraction schemes that can be used for scrubdescription D(i,k) generation.

To improve user experience, a layered flexible description scheme may beused in various embodiments. For instance:

<scruball>    <scrub class = ‘description’ degree=2 ......>     <degree1>......     </degree 1>     <degree 2>.......     </degree 2>   </scruball>

The scrub descriptions of different layers and different degrees may besaved in the same file or different files depending on differentconfiguration requirements. Noticeably, in most cases, it is desirableto save the descriptions in the same layer into the same file to reducemanagement and delivery cost.

Once the scrub description data is extracted, the manifest file and anindex file to facilitate description based scrub preview shall begenerated.

The index file listing the data structure of the scrub description isgenerated (step 1250). Information such as total number of layers K,total number of scrub descriptions (I_(k)) in a layer k, and timesegments Γ(i, k) maybe saved in the index file. Using the index file, amedia player can easily and quickly allocate the scrub description data.The index file indicates explicitly the location of scrub descriptionD(h, i, k) enabling the player to quickly extract the scrub descriptionfrom the scrub description file and display in an user friendly mannerfor preview.

A manifest file is generated (step 1260). The manifest file may includedifferent description and metadata to facilitate different uses of thedescription based scrub preview. For instance, the preview fileslocation, the overall metadata, such as title, genre, and producer info,and some scene description info, annotations, etc., may be included inthe manifest file. Noticeably, although, in one embodiment, the manifestfile is packaged separately from the scrub description data file, inanother embodiment, it may be packaged into the same file. Also, in oneembodiment, the manifest and the index file maybe compliant with theoriginal scrub preview manifest and index files whereas in anotherembodiment they may be different.

FIGS. 15 and 16 illustrate a detailed description of the operations ofthe PDD 320 (FIG. 11) in accordance with embodiments of the invention.

For the following description, assume T₀ is the time when a video streamVm is being delivered from the edge server to the client for playback,ΔT is the minimum buffer length for the player to start video playback,T^(D) _(M) is the starting time of the scrub description manifest filebeing delivered, T^(D*) _(M) is the ending time of the manifest filebeing delivered, T^(D) _(I) is the starting time of the scrubdescription index file being delivered, T^(D*) _(I) is the ending timeof the index file being delivered, T^(D)(k) is the starting time of thek^(th) scrub description data being delivered, and T^(D*)(k) is theending time of the k^(th) scrub description data being delivered. LetB^(th)(t) denote the available bandwidth between the server and theclient for content delivery at time t, R_(p)(t) denote the media playerplayback bitrate for Vm at time t, R_(vm)(t) denote the minimum deliverybitrate of Vm at time t to prevent playback jitter at the client,R^(D)(t) denote possible delivery bitrate of the preview file datastream at time t, and ΔR is a heuristic bitrate offset value to dealwith short time bandwidth variations.

In the following sample embodiment, we assume different layers of thescrub description data are packaged in different files where F^(D)(k)denotes the k^(th) layer scrub description data file with sizeSF^(D)(k). The manifest file with a file size SF^(D) _(M) is denoted asF^(D) _(M), and the index file with the file size SF^(D) _(I) is denotedas F^(D) _(I). A skilled in art can easily modify the embodiment whendifferent layers of the scrub description data are packaged in a singlepreview file or when different degrees of the scrub description data arepackaged in separate files. The minimum buffer length ΔT is governed bymany factors, such as the GOP size of a compressed video. Since thereare many literatures available in the field, a skilled in the art shouldbe able to calculate minimum buffer length ΔT based on the specificapplication requirement. Hence, a specific algorithm is not providedhere.

FIG. 15 illustrates a scheduling algorithm for a standalone previewsystem for the operations of the preview description delivery inaccordance with an embodiment of the invention.

At a first step 1510, the bit rate at the starting time B^(th)(T₀) iscompared with the minimum delivery bitrate of Vm at the starting time toprevent playback jitter at the client R_(vm)(T₀). If the availablebandwidth is positive after allowing for a margin for variousfluctuations, the scrub data file will be transmitted. In contrast, ifthere is no available bandwidth, bit rate adaptation will be undertakenas explained below in step 1610. The first file to be transmitted is themanifest file, which is transferred at a rate set by the availablebandwidth (Step 1530). Accordingly, at step 1520, at t=T^(D) _(M)=T₀, ifB_(th)(t)>R_(vm)(t), start delivering manifest file F^(D) _(M) with rateR^(D) _(M), where R^(D) _(M)=R^(D)(T₀)−ΔR, &R^(D)(T₀)=B_(th)(T₀)−R_(vm)(T₀). If B_(th)(T_(M))−R_(vm)(T_(M)) is notpositive, additional bit rate adaptation may be necessary and thereforego to Step 1610. At step 1610, bitrate adaptation is performed such thatB_(th)(t)>R_(vm)(t). Then delivery of the manifest file F^(D) _(M•) isstarted.

The time after completing the delivery of the manifest file F^(D) _(M)with rate R^(D) _(M) is

${T_{m}^{D*} = {T_{0} + \frac{{SF}_{M}^{D}}{R_{M}^{D}}}},$Therefore, at this ending time, the transmission of the index file isstarted (Steps 1540 and 1550) provided there is sufficient bandwidth. Inother words, at time

${t = {T_{M}^{D*} = {{{T_{I}^{D}\&}\mspace{14mu} T_{I}^{D}} = {T_{0} + \frac{{SF}_{M}^{D}}{R_{M}^{D}}}}}},$if B_(th)(t)>R_(vm)(t), start delivering index file F^(D) _(I) with rateR^(D) _(I)=R^(D)(T_(M))−ΔR, & R^(D)(T_(M))=B_(th)(T_(M))−R_(vm)(T_(M)).If B_(th)(T_(M))−R_(vm)(T_(M)) is not positive, additional bit rateadaptation may be necessary and therefore go to Step 1620. At step 1620,bitrate adaptation is performed such that B_(th)(t)>R_(vm)(t). Thendelivery of the index file F^(D) _(I) is started.

The time after completing the delivery of the index file F^(D) _(I) isthe end time

$T_{I}^{D*} = {T_{0} + \frac{{SF}_{M}^{D}}{R_{M}^{D}} + {\frac{{SF}_{I}^{D}}{R_{I}^{D}}.}}$Therefore, at this ending time, if there is sufficient bandwidth, i.e.,B_(th)(t)>R_(vm)(t), the sending of the first layer of the scrubdescription file F^(D)(1) is started (Steps 1560 and 1570), i.e., at

${t = {T_{I}^{D*} = {{{{T^{D}(1)}\&}\mspace{14mu}{T^{D}(1)}} = {T_{0} + \frac{{SF}_{M}^{D}}{R_{M}^{D}} + \frac{{SF}_{I}^{D}}{R_{I}^{D}}}}}},$if B_(th)(t)>R_(vm)(t), start delivering F^(D)(1), with rateR^(D)=R^(D)(T_(I))−ΔR, & R^(D)(T_(I))=B_(th)(T_(I))−R_(vm)(T_(I)).Again, if however if B_(th)(t)<R_(vm)(t), the go to Step 1630 forfurther adjustments. At step 1630, bitrate adaptation is performed suchthat B_(th)(t)>R_(vm)(t). Then delivery of the first layer of the scrubdescription file F^(D)(1) is started.

After completing the sending of the first layer of the scrub descriptionfile, the higher layers of the scrub description data are sent if thereis sufficient bandwidth (Steps 1580 and 1590), i.e.,B_(th)(t)>R_(vm)(t). In other words, at t=T^(D*)(k−1)=T^(D)(k), ifB_(th)(t)>R_(vm)(t), start delivering F^(D)(k), k=2, 3, . . . . If not,go to step 1640 for adjustments. At step 1640, bitrate adaptation isperformed such that B_(th)(t)>R_(vm)(t). Then delivery of the k^(th)layer of the scrub description file F^(D)(k) is started.

When different degrees of the scrub descriptions are packed in differentfiles, one added flexibility is to deliver the lowest degree first tofurther save bandwidth and deliver the higher degree ones on demand oronly when there is extra bandwidth. The schedule algorithm can be easilymodified accordingly.

FIG. 16 illustrates a scheduling algorithm for a standalone previewsystem for the operations of the preview description delivery inaccordance with an embodiment of the invention, wherein the schedulingalgorithm delivers granular layers from within the layers of the scrubdescription data.

In this embodiment, unlike the embodiment of FIG. 15, layers of thescrub description data D(i,k) are not delivered sequentially fork=[1,K]. Instead, a particular set of layers, k¹, k², . . . k^(Q), ispicked based on a decision criteria. In one embodiment, the decisioncriteria is selected as

$k^{q} = {K\;\frac{g^{q}}{Gn}}$where granularity selection parameter g^(q), qε[1,Q] defines thegranularity levels, and Gn defines the total levels of granularities.The granularity selection parameter g^(q) may be specified by the user,a user preference function, a bandwidth adaptation function, or otherfunctions that can jointly optimize resource and user preferences.

Referring to FIG. 16, the operations proceed similar to FIG. 15 intransferring the manifest file and the index file. Therefore, at steps1510 and 1520, at time t=T^(D) _(M)=T₀, if B_(th)(t)>R_(vm)(t), deliveryof manifest file F^(D) _(M) is initiated with a rate R^(D) _(M), whereR^(D) _(M)=R^(D)(T₀)−ΔR, & R^(D)(T₀)=B_(th)(T₀)−R_(vm)(T₀). Otherwise atstep 1610, bitrate adaptation is performed such thatB_(th)(t)>R_(vm)(t). Then delivery of the manifest file F^(D) _(M•) isstarted.

At steps 1530 and 1540, and as described above, at time

${t = {T_{M}^{D*} = {{{T_{I}^{D}\&}\mspace{14mu} T_{I}^{D}} = {T_{0} + \frac{{SF}_{M}^{D}}{R_{M}^{D}}}}}},$if B_(th)(t)>R_(vm)(t), delivery of index file F^(D) _(I) is startedwith a rate R^(D) _(I), where R^(D) _(I)=R^(D)(T_(M))−ΔR, &R^(D)(T_(M))=B_(th)(T_(M))−R_(vm)(T_(M)). Otherwise, at step 1620,bitrate adaptation is performed such that B_(th)(t)>R_(vm)(t). Thendelivery of the index file F^(D) _(I) is started.

Unlike the embodiment described in FIG. 15, the first layer of the scrubdescription file is not transmitted. Rather, the k¹ layer will betransmitted. The time after completing the delivery of the index fileF^(D) _(I) is the end time

$T_{I}^{D*} = {T_{0} + \frac{{SF}_{M}^{D}}{R_{M}^{D}} + {\frac{{SF}_{I}^{D}}{R_{I}^{D}}.}}$Therefore, at this ending time, if there is sufficient bandwidth, i.e.,B_(th)(t)>R_(vm)(t), the sending of the k¹ layer of the scrubdescription file F^(D)(k¹) is started (Steps 1710 and 1720). In otherwords, at time

${t = {T_{I}^{D*} = {{{{T^{D}( k^{1} )}\&}\mspace{14mu}{T^{D}( k^{1} )}} = {T_{0} + \frac{{SF}_{M}^{D}}{R_{M}^{D}} + \frac{{SF}_{I}^{D}}{R_{I}^{D}}}}}},$delivery of the k¹ scrub description data is started with rate R^(D) ifB_(th)(t)>R_(vm)(t). Here, R^(D)=R^(D)(T_(I))−ΔR, &R^(D)(T_(I))=B_(th)(T_(I))−R_(vm)(T_(I)). Otherwise, at step 1760,bitrate adaptation is performed such that B_(th)(t)>R_(vm)(t). Thendelivery of the k¹ layer of the scrub description file F^(D)(k¹) isstarted.

After completing the delivery of the k¹ layer of the scrub descriptionfile F^(D)(k¹), the next assigned layer (k^(q)) (q=2) of the scrubdescription file is sent if there is sufficient bandwidth (steps 1730and 1740). In other words, at time t=T^(D*)(k^(q-1))=T^(D)(k^(q)),delivery of the k^(q) scrub description data is started ifB_(th)(t)>R_(vm)(t). Subsequent assigned layers of the scrub description(q=3, 4, . . . ) may be sent similarly. Otherwise, at step 1770, bitrateadaptation is performed such that B_(th)(t)>R_(vm)(t). Then delivery ofthe k^(q) layer of the scrub description file F^(D)(k^(q)) is started.

Similarly, when different degrees of the scrub descriptions are packedin different files, only the file that contains the first degreedescription shall be delivered while the higher degree ones aretransported on demand or only when there is extra bandwidth.

In one or more embodiments, the preview description files may be savedin different server(s) instead of the original media. In this case,B_(th)(t) should be defined as the minimum available bandwidth betweenthe media server and the client and that between the preview descriptionserver and the client.

A detailed description and sample embodiments for a PDR 330 (FIG. 11)will now be described using FIG. 17.

FIG. 17 illustrates a sample embodiment of a PDR 330 at a media playerreceiving preview data in accordance with an embodiment.

To ensure playback at any preview points without any glitch, alignmentbetween the scrub description and the original media stream is needed.As discussed in the PDG section above, time segments Γ(i, k), which areregistered in the index file, facilitate synchronization.

In the following sample embodiment, the scrub description data arepackaged based on the location of the scrub description. That is, scrubdescription D(h, i, k) for hε[1, H] & iε[1, I_(k)] are packaged in thesame file. H is the maximum degree of freedom as described above. I_(k)is the total number of scrub descriptions in layer k. Again, a personskilled in the art can easily modify the embodiment when all scrubdescription D(h, i, k) for Iε[1, I_(k)] and kε[1, K] are packaged into asingle file or when for hε[1, H] are packaged in H different files.

Referring to FIG. 17, the media player receives the manifest file (step1810). Next, the media player receives the index file (step 1820). Ifthe scheduling algorithm described with respect to FIG. 15 is used, themedia player downloads the 1^(st) layer preview file (step 1830).Subsequently, the media player downloads the k^(th) layer preview file(step 1840).

FIG. 18 illustrates a sample embodiment of a PDR 330 at a media playerreceiving preview data in accordance with an embodiment.

FIG. 18 illustrates a media player receiving preview data from a serverusing the PDD algorithm illustrated in FIG. 16 while FIG. 17 illustratesa media player receiving preview data from a server using the PDDalgorithm illustrated in FIG. 15. Therefore, referring to FIG. 18, theSteps of 1810 and 1820 indicating the receipt of the manifest and indexfiles remain the same as in the prior embodiment. Referring to Step1910, k¹ layer preview file is received. Next, the media playerdownloads the k^(q) layer preview file. As described above, k¹, k^(q)layers are not delivered sequentially and may be selected using variouscriterion.

FIG. 19 illustrates a media player receiving preview data havingmultiple degrees of freedom in accordance with an embodiment of theinvention.

Referring to FIG. 19, when the scrub description data with multipledegrees of freedom D(h,i,k) for hε[1,H] are packaged in different files,multiple files have to be downloaded. Accordingly, a first set of filesare downloaded for the first degree of freedom. As in previousembodiments, the manifest file and the index file are received (Steps1810 and 1820). Next, the first degree of the first layer preview datais received (Step 2010) following by the first degree of the k^(th)layer of the preview data (Step 2020).

At client's request or when additional bandwidth is detected (Step2030), the media player starts to download the additional degree previewfiles in order from h=2 to h=H (Steps 2040 and 2050). The media playerdoes not always need to download all the scrub description data filesdescribed in the manifest file. The number k may be decided based onuser preference, the network conditions, the end to end availablebandwidth and possibly other factors defined by the media player.

With a first layer scrub description data file, a user can get a coarsegrain preview experience. After getting the following layers of scrubdescription data files, the user can enjoy finer grain previewexperiences. In the meantime, with a first degree scrub description, auser gets some rough description and when additional descriptions aredownloaded detailed description at each segment in each layer can beobtained.

For fast preview startup, the first layer scrub description data couldbe delivered before or right after the video starts to play back invarious embodiments. Since the scrub description data is small bydesign, users can begin with the preview almost instantly. Based on userpreference, the scrub description data might even be delivered beforeany of the original media data stream is being delivered. In this case,users can start browsing (preview) the story while the original mediadata stream is being buffered for playback. This is an alternative wayto reduce user waiting time and hence improves the overall video accessexperience.

To facilitate instant playback from any scrub preview point D(i*, k),time segments Γ(1, k), Γ(2, k) . . . Γ(i*−1, k) are obtained from theindex file. The end of all time segments available, which is theavailable preview length, be denoted as t*, which can be defined as

$t^{*} = {\sum\limits_{i = 1}^{i^{*} - 1}{{\Gamma( {i,k} )}.}}$The available preview length t* is compared with the buffer. If theavailable preview length t* runs outside of the buffer, the media playermay communicate with the edge server immediately to acquire thecorresponding media segments from the original media data stream serverto facilitate instant startup. Otherwise, the playback startsimmediately at the original media segment that corresponds to t*.

Another possible embodiment of the stand-alone implementation takesadvantage of the audio channel. That is, the scrub descriptions areplayed back in audio similar to a narrator instead of displayed as text.In this embodiment, still, multiple degrees and multiple layers of scrubpreviews can be facilitated and a skilled in the art can implementsimilar algorithms for PDG, PDD, and PDR.

Another embodiment that includes an add-on implementation will now bedescribed. In this case, the scrub descriptions can be used as one ormore added layers to the keyframe based scrub preview. In thisembodiment, the scrub description data may be scheduled for deliveryfirst with the first layer of the keyframes delivered next. Forinstance, the first layer of the preview keyframes can be scheduled fordelivery at T^(D*)(K) or T^(D*)(K^(Q)) using similar algorithms asdescribed in FIG. 15 or FIG. 16. When scrub descriptions are added asadditional layers to the keyframe based scrub preview, the scrubdescription and the keyframe images may not need to be synchronized.

FIG. 20 illustrates a sample interface for a dual-view scrub preview inaccordance with an embodiment of the invention. In this embodiment, bothdual-view and toggled view can be realized using the dual viewimplementation. When a dual-view scrub preview is implemented, thepreview keyframe and the corresponding scrub description text of aparticular time frame of the video stream are displayed in a dual-viewscrub preview window 61 as illustrated in FIG. 20. The dual-view scrubpreview window 61 includes a scrub description text window 61 a and akeyframe image 61 b.

In various embodiments, the dual-view scrub preview window 61 may beconfigured differently in terms of the relative location of the scrubdescription text window 61 a versus the location of the keyframe image61 b. For example, the user at the media player may configure thelocations and view of the scrub description text window 61 a and thekeyframe image 61 b. Embodiments of the present invention do not limitthe type of configurations of the preview window.

In addition, in one or more embodiments, the description text forpreview may be presented in audio format (in addition to or in place ofthe text format which is illustrated). The audio description has tostart from the position where the playhead is moved to and paused at. Insome embodiments, the preview images may be enhanced to be a series ofshort video clips which will auto-play when the playhead is scrubbed.

Often when video content is relatively long and the description textsare scattered along the progress bar, marker (range indicator 70, e.g.,as illustrated in FIG. 20) may be introduced along the progress bar tofacilitate the preview and content navigation efforts. In variousembodiments, the description text can be tailored to country/regionwhere the viewing is being requested so that correct language option canbe made available (based on GPS, client location as seen from CDN, oruser request from the media player).

In a toggled view scrub preview implementation, in one embodiment,either the keyframe image or the scrub description text/audio will bedisplayed in the scrub preview window. The view can be toggled from onetype to the other using a hot key combination or other access method.

In the dual view scrub preview implementation, the scrub description maybe synchronized with the keyframe images for ease of management and fastaccessibility. That is, one keyframe KF(j,k) and one scrub descriptionD(j, k) should be extracted from the same video segment Γ(j,k). Here,keyframe KF(j,k) and scrub description D(j, k), jε[1,J_(k)] denotes thekeyframe and the corresponding scrub description of the jth segmentΓ(j,k) in the kth layer preview. In contrast, the scrub description andthe keyframe images need not be synchronized when scrub descriptions areadded as additional layers to the keyframe based scrub preview.

Similar extraction schemes for scrub description D(j, k) describedearlier, e.g., FIGS. 12-14, may be used in this embodiment. Thekeyframes KF(j,k) may be extracted using any suitable scheme known toone skilled in the art. For each layer, all keyframes KF(j,k)s and scrubdescription D(j, k)s for jε[1,J_(k)] may be packaged into a single dualview scrub data file F^(DL)(k) or packaged separately in various ways.In the following description, one single file per layer is used as anexample. A single manifest file and a single index file may be generatedfor the entire preview data set that includes both the keyframes and thescrub descriptions in all layers.

For the preview delivery step, a slightly modified scheduling algorithmbased on those described in FIGS. 15 and/or 16 may be employed. First,the manifest file and the index file are delivered. Then, the dual viewscrub data file F^(DL)(k) may be delivered in a layer by layer fashionwith the lower layers delivered first.

At the media player side, the media player may download the dual viewscrub data file F^(DL)(k) after the manifest file and the index file aredownloaded, starting from k=1. A toggled view or a dual-view scrubpreview is achieved by displaying keyframes KF(j,k) and scrub data D(j,k) during the corresponding time frame Γ(j,k) in a toggled view or adual-view fashion.

An embodiment of the invention describing the use of pertinent richmedia scrub preview will now be described using FIG. 21. FIG. 21illustrates a media player 50 rendering a media rich scrub previewwindow 62. In addition to the description data, it is possible tointroduce other types of data or relevant information to facilitateadditional scrub preview capabilities. For instance, when watching asports game video, the users might be interested in information relevantto the sports teams or star players, recent game information, andpossibly merchandize that is related to the type of sports, the gameseason, or the relevant teams. These and other relevant information canall serve as part of the database to generate the scrub preview. Thescrub preview may be presented in a rich media format with video, image,graph, text, and any other type of media data incorporated into a singlemedia rich scrub preview window 62 to provide preview and browsingservices. A person skilled in the art can easily modify the generation,delivery, and rendering schemes discussed above in other embodiments andoptimize it for this embodiment.

In yet another embodiment of the present invention, an independentpreview service can be offered. Any user can subscribe to the previewservice with or without the subscription to the VoD or real time videodelivery service. A user subscribed to the preview service can beconnected directly to the preview server at her request. The servershall deliver the preview content to the user based on her subscriberservice class, the user profile, the network and device condition, etc.In this embodiment, the preview service server maybe connected tomultiple video delivery servers that are part of a single or multiple IPvideo delivery service providers. The generic architecture of such asystem may be implemented as illustrated in FIG. 10.

FIG. 22 illustrates a preview generation unit in accordance withembodiments of the invention. The preview generation unit may be the PG10 (FIG. 1) or the PDG 310 (FIG. 11) in various embodiments. Referringto FIG. 22, a preview generation unit 2210 comprises a preview datagenerator 2220 configured to generate a preview data. The preview datagenerator 2220 comprises a preview data extractor 2230 configured toextract preview information from a media file to be streamed. Thepreview data generator 2220 is configured to generate a preview datathat has a multi-dimensional hierarchical data structure having aplurality of layers. The content of the preview information in eachlayer increases in moving upto higher layers of the plurality of layers.The preview data generator 2220 is configured to provide adifferentiated preview service.

FIG. 23 illustrates a preview delivery unit in accordance withembodiments of the invention. The preview delivery unit may be the PD 20(FIG. 1) or the PDD 320 (FIG. 11) in various embodiments. Referring toFIG. 23, a preview delivery unit 2310 comprises a preview datatransmitter 2320 configured to send a preview data comprising previewinformation from a media file to be streamed. The preview datatransmitter 2320 is configured to send a multi-dimensional hierarchicaldata structure having a plurality of layers, e.g., stored in a single ora plurality of files in a non-transitory non-volatile storage medium.The content of the preview information in each layer increases in movingup to higher layers of the plurality of layers. The preview datatransmitter 2320 is configured to provide a differentiated previewservice.

FIG. 24 illustrates a preview receiver unit in accordance withembodiments of the invention. The preview receiver unit may be the PR 30(FIG. 1) or the PDR 330 (FIG. 11) in various embodiments. Referring toFIG. 24, a preview receiver unit 2410 comprises a user data transmitter2420 configured to send a preview data request to a preview server. Thepreview data request comprises a request for preview data. The previewreceiver unit 2410 further comprises a media player receiver 2430configured to receive a preview data comprising preview information. Thereceived preview data comprises a multi-dimensional hierarchical datastructure having a plurality of layers with increasing content of thepreview information in each layer of the plurality of layers.

FIG. 25 illustrates a representative a preview server in accordance withembodiments of the invention.

The preview server 2500 includes a receiver 2510, which may include awireless antenna receiver and/or a wired network connection port forreceiving the media content, for example, if it is stored at a remotelocation. The preview server 2500 also includes a memory 2530, which mayinclude both a non-volatile memory and a volatile memory. In oneembodiment, instructions for performing the operations described withrespect to FIGS. 1, 8, 9, 11, 12, 15-16 may be stored in anon-transitory storage medium such as a magnetic storage medium or asolid state storage medium in the memory 2530.

The preview server 2500 may include further I/O devices 2550 forinputting and outputting data. For example, the I/O devices 2550 mayinclude an optical disc such as a laser readable medium, for example, acompact disc reader, a blue ray disk reader, and/or digital video readeretc. In one or more embodiments, the instructions for performing theoperations as described in FIGS. 1, 8, 9, 11, 12, 15-16 may be stored inan optical disc, which is a non-transitory storage medium.

The preview server 2500 may also include a display 2560 and atransmitter 2540 for transmitting the preview data. The transmitter 2540may include plurality of wireless antennas and/or a wired port. Thetransmitter 2540 and the receiver 2510 can be combined together in someembodiments.

The preview server 2500 includes a processor 2520 configured to executethe instructions for performing the operations described with respect toFIGS. 1, 8, 9, 11, 12, 15-16 as well as FIGS. 22 and 23. The processor2520 may comprise a single processor or a plurality of processors.

FIG. 26 illustrates a representative a media player in accordance withembodiments of the invention.

The media player 2600 includes a media player (MP) receiver 2610, whichmay include a wireless antenna receiver and/or a wired networkconnection port for receiving the media content, for example, if it isstored at a remote location. The MP receiver 2610 may be used by themedia player 2600 to receive the preview data files. The media player2600 also includes a MP memory 2630, which may include both anon-volatile memory and a volatile memory. In one embodiment,instructions for performing the operations described with respect toFIGS. 1, 10-11, 17-19, and 24 may be stored in a non-transitory storagemedium such as a magnetic storage medium or a solid state storage mediumin the MP memory 2630.

The media player 2600 may include further MP I/O devices 2650 forinputting and outputting data. For example, the MP I/O devices 2650 mayinclude an optical disc such as a laser readable medium, for example, acompact disc reader, a blue ray disk reader, and/or digital video readeretc. In one or more embodiments, the instructions for performing theoperations as described in FIGS. 1, 10-11, 17-19, and 24 may be storedin an optical disc, which is a non-transitory storage medium.

The media player 2600 may also include a MP display 2560 and a MPtransmitter 2540 for transmitting the user specified parameter data. TheMP transmitter 2640 may include plurality of wireless antennas and/or awired port. The MP transmitter 2640 and the MP receiver 2610 can becombined together in some embodiments.

The media player 2600 includes a MP processor 2620 configured to executethe instructions for performing the operations described with respect toFIGS. 1, 10, 11, 17-19, as well as FIG. 24. The MP processor 2620 maycomprise a single processor or a plurality of processors.

FIG. 27 illustrates a generic architecture of a system implementing thedifferentiated scrub preview in accordance with embodiments of theinvention.

Referring to FIG. 27, a plurality of video servers 2720 may be serving amedia stream to a client 2730. Upon request, a preview server 2710 mayserve the client 2730 with a preview data stream. In variousembodiments, the preview server 2710 may be a standalone server or maybe part of a video server 2720.

Although not specifically disclosed, embodiments of the invention can becombined. For examples, embodiments described with respect to FIGS. 8-10may be combined with the embodiments described with respect to FIGS.11-21. For example, an integrated data structure may include bothpreview data type and scrub description data as different dimensions inone or more embodiments.

A number of features and advantages can be obtained from variousembodiments of the invention. For example, in one aspect, the inventionprovides a system for description based scrub preview generation,delivery, and presentation via an online media player to facilitate fastscrub preview even when the network bandwidth is low. In another aspect,an on-demand video preview method that allows user to browse the videocontent, even the portion that is not currently buffered and to startbrowsing instantly on any terminal device and almost under any networkcondition including networks with very low bandwidth and/or frequentbandwidth fluctuations. This feature offers an informed viewingexperience and provides convenient video browsing and searchingcapability with a natural drag and play functionality. In anotheraspect, a set of schemes for dual view preview generation, delivery, andpresentation which offers both dual-view and toggled view scrub previewfunctionality is provided. In yet another aspect, a layered scrubdescription data structure, a synchronization scheme, along with adelivery scheme for fast preview startup while offering personalizedpreview experience is provided.

In a further aspect, a multi-degree scrub preview scheme to facilitateinstant preview startup and personalized preview services is provided.In yet a further aspect, two delivery scheduling schemes can beconfigured for delivery at various optimal time points to minimizestartup delay and playback jitter and/or configured for personalizeddelivery. In another aspect, a personalized description based scrubpreview presentation scheduling scheme offers an alternativefunctionality to reduce user wait time at start up.

Embodiments of the present invention extend the scrub preview to provideultra-fast preview startup functionality. In one or more embodiments,description based scrub preview are offered instead of keyframe basedscrub preview. The preview can start instantly without affecting theplayback of the video, even in very low bandwidth network conditions. Ina separate embodiment, the present invention describes the systems andscheme to achieve an additional scrub preview style called dual viewscrub preview that takes advantage of both the description based and thekeyframe based scrub preview. The dual view scrub preview offersadditional personalized service capability. Embodiments of the presentinvention address the system and method to realize the description basedscrub preview as well as the dual view scrub previews in a networkedmedia distribution system with an online media player.

While this invention has been described with reference to illustrativeembodiments, this description is not intended to be construed in alimiting sense. Various modifications and combinations of theillustrative embodiments, as well as other embodiments of the invention,will be apparent to persons skilled in the art upon reference to thedescription. It is therefore intended that the appended claims encompassany such modifications or embodiments.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. For example,many of the features and functions discussed above can be implemented insoftware, hardware, or firmware, or a combination thereof.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

What is claimed is:
 1. A method of streaming a media preview of a mediaover a network, the method comprising: receiving a request to deliver apreview data comprising preview information for a media file beingstreamed to a client through the network, wherein the preview datacomprises a multi-dimensional hierarchical data structure having aplurality of layers with increasing content of the preview informationin each layer of the plurality of layers, wherein the preview data isconfigured to provide an adaptive and scalable preview service, whereinthe preview data comprises scrub description information, wherein thepreview data comprises a plurality of preview locations on a timeline ofthe media file being streamed, and wherein each preview location isassociated with a corresponding time frame on the timeline of the mediafile being streamed; and delivering preview information to be displayedat the client through the network, wherein the preview information isfrom a layer of the plurality of layers of the preview data, whereindelivering preview information to be displayed at the client through thenetwork comprises: receiving a request for the preview data; determiningwhether bandwidth is available for sending a manifest file withoutcausing playback jitter while rendering the media file to be streamed;sending the manifest file in response to determining that bandwidth isavailable for sending the manifest file; and performing bit rateadaptation and then sending the manifest file in response to determiningthat bandwidth is not available for sending the manifest file.
 2. Themethod of claim 1, wherein the adaptive and scalable preview serviceprovides a differentiated preview service.
 3. The method of claim 1,wherein the preview data comprises preview data type information.
 4. Themethod of claim 3, wherein delivering preview information to bedisplayed at the client through the network comprises: receiving aservice request from the client; generating an instantaneous userservice profile identifying a layer of preview data for each type ofpreview data; identifying the layer of the preview data in theinstantaneous user service profile to be transmitted; extracting aspecific preview information in the layer of the preview data; andsending the specific preview information to the client.
 5. The method ofclaim 3, wherein delivering preview information to be displayed at theclient through the network comprises: receiving a user parameter from aclient over the network; defining a preview description data and/ornetwork transmission parameters based on the user parameter; and usingthe defined preview description data and/or network transmissionparameters, sending the preview description data to the client over thenetwork.
 6. The method of claim 1, wherein delivering previewinformation to be displayed at the client through the network comprises:sending a manifest file comprising additional description and/ormetadata; sending an index file after sending the manifest file; andsending a scrub description file comprising the scrub descriptioninformation, wherein the manifest file, the index file, and the scrubdescription file are sent without causing playback jitter whilerendering the media file to be streamed, and wherein the index filedescribes the structure of the scrub description file.
 7. The method ofclaim 1, wherein delivering preview information to be displayed at theclient through the network further comprises: determining whetherbandwidth is available for sending an index file without causingplayback jitter while rendering the media file to be streamed; sendingthe index file if bandwidth is available for sending the index file, theindex file being started to send after completing sending the manifestfile; and performing bit rate adaptation if bandwidth is not availablefor sending the index file.
 8. The method of claim 1, wherein deliveringpreview information to be displayed at the client through the networkfurther comprises: determining whether bandwidth is available forsending a first scrub file comprising a first layer of a scrubdescription without causing playback jitter while rendering the mediafile to be streamed; sending the first scrub file if bandwidth isavailable for sending the first scrub file; performing bit rateadaptation if bandwidth is not available for sending the first scrubfile; determining whether bandwidth is available for sending a secondscrub file comprising a k^(th) layer of the scrub description withoutcausing playback jitter while rendering the media file to be streamed,wherein the k^(th) layer is any layer from the plurality of layers ofthe multi-dimensional hierarchical data structure; sending the secondscrub file if bandwidth is available for sending the second scrub file,the second scrub file being started to send after completing sending thefirst scrub file; and performing bit rate adaptation if bandwidth is notavailable for sending the second scrub file.
 9. The method of claim 8,wherein sending of the first scrub file is started after completingsending an index file.
 10. The method of claim 1, wherein deliveringpreview information to be displayed at the client through the networkcomprises: determining whether bandwidth is available for sending afirst scrub file comprising a k¹ layer of a scrub description withoutcausing playback jitter while rendering the media file to be streamed;sending the first scrub file if bandwidth is available for sending thefirst scrub file; performing bit rate adaptation if bandwidth is notavailable for sending the first scrub file; determining whetherbandwidth is available for sending a second scrub file comprising ak^(q) layer of the scrub description without causing playback jitterwhile rendering the media file to be streamed, wherein the k¹ layer andthe k^(q) layer are layers from the plurality of layers of themulti-dimensional hierarchical data structure, and wherein the k¹ layerand the k^(q) layer are selected based on a decision criterion; sendingthe second scrub file if bandwidth is available for sending the secondscrub file, the second scrub file being started to send after completingsending the first scrub file; and performing bit rate adaptation ifbandwidth is not available for sending the second scrub file.
 11. Themethod of claim 10, wherein the decision criterion comprises selecting alevel of granularity from the plurality of layers.
 12. The method ofclaim 11, wherein the decision criterion is selected a${k^{q} = {K\frac{g^{q}}{Gn}}},$ and where a granularity selectionparameter g^(q), qε[1,Q], defines the level of granularity, and Gndefines a total number of levels of granularities.
 13. The method ofclaim 12, wherein the granularity selection parameter g^(q) is specifiedby a media player.
 14. The method of claim 12, wherein the granularityselection parameter g^(q) is specified by a user preference functionand/or a bandwidth adaptation function.
 15. The method of claim 10,wherein sending of the first scrub file is started after completingsending an index file.
 16. The method of claim 1, wherein the previewdata comprises scrub description information and keyframe images. 17.The method of claim 16, wherein delivering the preview information to bedisplayed at the client through the network comprises, at each layer,sending the scrub description information and then sending the keyframeimages.
 18. The method of claim 16, wherein, at each layer, the scrubdescription information and keyframe images are combined into a singledual view preview data file, and wherein delivering the preview datacomprises sending the single dual view preview data file.
 19. The methodof claim 1, wherein the preview data comprises scrub preview configuredto be displayed when a play-head is moved forward or backward along apreview bar.
 20. An apparatus for streaming a media preview of a mediaover a network, the apparatus comprising: a preview data senderconfigured to receive a request to deliver a preview data to a clientthrough the network, the preview data comprising preview information fora media file being streamed, wherein the preview data comprises amulti-dimensional hierarchical data structure having a plurality oflayers with increasing content of the preview information in each layerof the plurality of layers, wherein the preview data sender isconfigured to provide an adaptive and scalable preview service, whereinthe preview data comprises scrub description information, wherein thepreview data comprises a plurality of preview locations on a timeline ofthe media file being streamed, and wherein each preview location isassociated with a corresponding time frame on the timeline of the mediafile being streamed; and wherein the preview data sender is furtherconfigured to deliver the layer of the preview data comprising previewinformation to be displayed at the client through the network, whereinthe preview data sender comprises: a preview data request receiverconfigured to receive a request for the preview data; a manifest filebandwidth determinator configured to determine whether bandwidth isavailable for sending a manifest file without causing playback jitterwhile rendering the media file to be streamed; a manifest file bit rateadaptor configured to perform bit rate adaptation in response to themanifest file bandwidth determinator determining that bandwidth is notavailable for sending the manifest file; and a manifest file senderconfigured to send the manifest file in response to the manifest filebandwidth determinator determining that bandwidth is available forsending the manifest file, send the manifest file after performing bitrate adaptation in response to the manifest file bandwidth determinatordetermining that bandwidth is not available for sending the manifestfile.
 21. The apparatus of claim 20, wherein the adaptive and scalablepreview service provides a differentiated preview service.
 22. Theapparatus of claim 20, wherein the preview data comprises preview datatype information.
 23. The apparatus of claim 22, wherein the previewdata sender comprises: a service request receiver configured to receivea service request from a client; an instantaneous user service profilegenerator configured to generate an instantaneous user service profileidentifying a layer of preview data for each type of preview data; alayer identifier configured to identify the layer of the preview data inthe instantaneous user service profile to be transmitted; a previewinformation extractor configured to extract a specific previewinformation in the layer of the preview data; and a preview informationsender configured to send the specific preview information to theclient.
 24. The apparatus of claim 22, wherein the preview data sendercomprises: a user parameter receiver configured to receive a userparameter from a client; a preview description data estimator configuredto define a preview description data and/or network transmissionparameters based on the user parameter; and a preview description datasender configured to send the preview description data to the clientusing the defined preview description data and/or network transmissionparameters.
 25. The apparatus of claim 20, wherein the preview datasender comprises: a manifest file sender configured to send a manifestfile comprising additional description and/or metadata; an index filesender configured to send an index file after sending the manifest file;and a scrub description file sender configured to send a scrubdescription file comprising the scrub description information, whereinthe manifest file, the index file, and the scrub description file areconfigured to be sent without causing playback jitter while renderingthe media file to be streamed, and wherein the index file describes thestructure of the scrub description file.
 26. The apparatus of claim 20,wherein the preview data sender further comprises: an index filebandwidth determinator configured to determine whether bandwidth isavailable for sending an index file without causing playback jitterwhile rendering the media file to be streamed; an index file senderconfigured to send the index file if bandwidth is available for sendingthe index file, the index file sender configured to start sending theindex file after completing sending the manifest file by the manifestfile sender; and an index file bit rate adaptor configured to performbit rate adaptation if bandwidth is not available for sending the indexfile.
 27. The apparatus of claim 20, wherein the preview data sendercomprises: a first scrub file determinator configured to determinewhether bandwidth is available for sending a first scrub file comprisinga first layer of a scrub description without causing playback jitterwhile rendering the media file to be streamed; a first scrub file senderconfigured to send the first scrub file if bandwidth is available forsending the first scrub file; a first scrub file bit rate adaptorconfigured to perform bit rate adaptation if bandwidth is not availablefor sending the first scrub file; a second scrub file determinatorconfigured to determine whether bandwidth is available for sending asecond scrub file comprising a k^(th) layer of the scrub descriptionwithout causing playback jitter while rendering the media file to bestreamed, wherein the k^(th) layer is any layer from the plurality oflayers of the multi-dimensional hierarchical data structure; a secondscrub file sender configured to send the second scrub file if bandwidthis available for sending the second scrub file, the second scrub filesender configured to start sending the second scrub file after the firstscrub file sender completes sending the first scrub file; and a secondscrub file bit rate adaptor configured to perform bit rate adaptation ifbandwidth is not available for sending the second scrub file.
 28. Theapparatus of claim 27, wherein the first scrub file sender startssending the first scrub file after an index file sender completessending an index file.
 29. The apparatus of claim 20, wherein thepreview data sender comprises: a first scrub file determinatorconfigured to determine whether bandwidth is available for sending afirst scrub file comprising a k¹ layer of a scrub description withoutcausing playback jitter while rendering the media file to be streamed; afirst scrub file sender configured to send the first scrub file ifbandwidth is available for sending the first scrub file; a first scrubfile bit rate adaptor configured to perform bit rate adaptation ifbandwidth is not available for sending the first scrub file; a secondscrub file determinator configured to determine whether bandwidth isavailable for sending a second scrub file comprising a k^(q) layer ofthe scrub description without causing playback jitter while renderingthe media file to be streamed, wherein the k¹ layer and the k^(q) layerare layers from the plurality of layers of the multi-dimensionalhierarchical data structure, and wherein the k¹ layer and the k^(q)layer are selected based on a decision criterion; a second scrub filesender configured to send the second scrub file if bandwidth isavailable for sending the second scrub file, the second scrub filesender configured to start sending the second scrub file after the firstscrub file sender finishes sending the first scrub file; and a secondscrub file bit rate adaptor configured to perform bit rate adaptation ifbandwidth is not available for sending the second scrub file.
 30. Theapparatus of claim 29, wherein the decision criterion comprises a levelof granularity from the plurality of layers.
 31. The apparatus of claim30, wherein the decision criterion is given by a formula${k^{q} = {K\frac{g^{q}}{Gn}}},$ and where a granularity selectionparameter g^(q), qε[1,Q], defines the level of granularity, and Gndefines a total number of levels of granularities.
 32. The apparatus ofclaim 31, wherein the granularity selection parameter g^(q) is specifiedby a media player.
 33. The apparatus of claim 31, wherein thegranularity selection parameter g^(q) is specified by a user preferencefunction and/or a bandwidth adaptation function.
 34. The apparatus ofclaim 29, wherein the first scrub file sender starts sending the firstscrub file after an index file sender completes sending an index file.35. The apparatus of claim 20, wherein the preview data comprises scrubdescription information and keyframe images.
 36. The apparatus of claim35, wherein the preview data sender comprises, at each layer, a scrubdescription information sender configured to send the scrub descriptioninformation and then send the keyframe images.
 37. The apparatus ofclaim 35, further comprising a combinator configured to combine thescrub description information and keyframe images into a single dualview preview data file at each layer, and wherein the preview datasender is configured to send the single dual view preview data file. 38.The apparatus of claim 20, wherein the preview data comprises scrubpreview configured to be displayed when a play-head is moved forward orbackward along a preview bar.